Ok, this should be the last round of buffer refresh fixes. Switching fullscreen with filters on should now work correctly for the SDL port.

zsnes/src/gui/guikeys.inc

@@ -1185,27 +1185,28 @@ GUIVideoKeys:
   je near .nosuper2xsai
   cmp dh,'X'
   jne .no2xsai
-  GUIkeystoggleoptn byte[En2xSaI],1
+  mov eax,1
   jmp .yesfilter
 .no2xsai
   cmp dh,'E'
   jne .nosupereagle
-  GUIkeystoggleoptn byte[En2xSaI],2
+  mov eax,2
   jmp .yesfilter
 .nosupereagle
   cmp dh,'S'
   jne .nosuper2xsai
-  GUIkeystoggleoptn byte[En2xSaI],3
+  mov eax,3
 .yesfilter
+  pushad
+  call Clear2xSaIBuffer
+  popad
   mov byte[hqFilter],0
   mov byte[scanlines],0
   mov byte[cfgscanline],0
   mov byte[antienab],0
   mov byte[cfginterp],0
   mov byte[NTSCFilter],0
-  pushad
+  GUIkeystoggleoptn byte[En2xSaI],al
-  call Clear2xSaIBuffer
-  popad
 .nosuper2xsai
   cmp dh,'I'
   jne .nointerpolation

zsnes/src/gui/guimouse.inc

@@ -893,6 +893,7 @@ SECTION .text
 
 NEWSYM SwitchFullScreen
   pushad
+  call Clear2xSaIBuffer
   xor eax,eax
   mov al,[cvidmode]
   cmp byte[GUIWFVID+eax],0

zsnes/src/linux/gl_draw.c

@@ -265,7 +265,7 @@ void gl_drawwin()
 				// (see ProcessTransparencies in newgfx16.asm
 				//  for ZSNES' current transparency code)
 	UpdateVFrame();
-	if (curblank != 0)
+	if (curblank || cvidmode<6)
 		return;
 
 	if (BilinearFilter)